OK... let's get this one right (according to fencersmother's morality):
After a weekend of discernment with Mom & Dad, Grandpa & Grandma, etc., should you decide you will accept your appointment, put those papers in Pile A. Now, look at your other acceptances, your Plan B, if you will. CALL THAT SCHOOL Monday morning and explain the situation. Many schools will allow you to put down your deposit to hold a space, knowing that you are going to USAFA or USMA or USNA etc, with the full understanding that you will forfeit that money (still a wise investment) should Junior not show up. Twin A put $250 down to hold a spot at his plan B school, which they very very graciously refunded to me. Twin B put $700 to hold his spot, and that liberal east coast LAC kept his money and attempted to charge me something extra (after they'd agreed not to do so). No names , but still hard feelings about that institution.
Classes at USAFA start very early in August so chances are you will know whether Jr has made it through BCT and begun the academic year with enough time to get installed at School B.
If Jr stays at USAFA, yes, you lose your $$$, and it's a lot of money.
You'll have to work out your own arrangements with the ROTC folks as I am too long out of the loop for those convoluted shenanigans.
If you have any questions, just pm me (when you post enough to have pm privileges).